Abstract

Background: Due to the side effects of chemical medicines, nowadays the use of drugs of natural origin is concerned. In traditional medicine plants of Ferula family generally regarded as the inhibitor of pain and inflammation. In this study using the sub-plantar formalin injection the anti-inflammatory effect of the hydroalcoholic extract of Ferula szowitsiana DC., as one of the species of this family, is investigated on rat paw edema. Materials and Methods: The hydroalcoholic extract of Ferula szowitsiana DC. was prepared and solved in Saline, Ethanol and Tween 80 (in a ratio of 8:1:1, respectively). Male Wistar rats (200-250 g) were assigned to: Control, Solvent (i.p), Solvent (i.t), Extract (50, 100, 200, 400 mg/kg, i.p), Naloxone (2 mg/kg, i.p), Naloxone-Extract (2 mg/kg, i.p and 400 mg/kg, i.p, respectively) and Extract (8 &amp;mu;g/10 &amp;mu;l, i.t) groups. For inducing inflammation Formalin 2.5 (0.05 ml) and for assessing the volume of edema plethysmometeric methods were used. Results: The extract of Ferula szowitsiana DC. reduced inflammation in a dose dependent manner (P&lt;0.001). The effects of central (i.t.) administration of the equivalent concentration of the effective dose of extract were similar to their systemic administration. Naloxone partially reduced the anti-inflammatory effect of extract (P&lt;0.05). Conclusion: The anti-inflammatory property of Ferula szowitsiana DC. extract is probably induced because of its effect on central nervous system (CNS) and part of this effect is mediated by opioid system.